Helicopter propeller



D66. a I I I KOGLER ,510,689

v HELICOPTER FROPELLER File 1m 1925 2 Sheets-Sheet l f/ I: l (,1?

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l atented Dec. 14, 1926.

UNITED STATES ALBERT KCGLER, OF SAN FRANCISCO, CALIFORNTA.

HELICOPTER PROPELLER.

Application filed June 17, 1925. Serial No. 37,602.

This invention relates to propellers and especially to that type employed in helicopter flying machines.

The object of the present invention is to generally improve and simplify the construction and operation of propellers of the character described; to provide a propeller in which the blades are radially disposed and arranged in helical formation, each of which forms a part of a helix; and further to provide a propeller which may employ numerous blades which combined present a large area which produces a proportionate lifting capacity. 7

One form which my invention may assume is exemplified in the following description and illustrated in the accompanying drawings, in which- Fig. 1 is a perspective view of the propeller.

Fig. 2 is an enlarged detail section showing the manner of attaching the propeller blades to the frame.

Fig. 3 is a perspective view showing the manner of forming and cutting the propeller blades.

Referring to the drawings in detail and particularly to Fig. 1, it will be noted that the propeller consists of a blade section A and a cylindrical shaped frame section B by which the blades are supported and rotated. The frame consists of a central hub 2 and a plurality of radially disposed arms or spokes 3, a plurality of vertically disposed posts or rods 4, and a plurality of hel'tcally disposed rods which are indicated at 5, 6, 7, and 8. These rods carry the blades A and the blades are accordingly arranged in helical formation about the cylindrical frame. The inner end of each blade is reinforced as indicated at 9 and'each blade carries a threaded bolt 10 which passes through the helical rods where it is secured by a nut 11 as shown in Fig. 2. This manner of fastening the blades N in the frame is important as it permits the pitch or incline of the individual blades to be increased or decreased as desired. The manner in which the blades are formed is also of considerable importance. This feature is particularly illustrated in Fig. 3. A wooden or metallic block C is employed. The block has a helical surface formed thereon generally indicated at D. A strip of metal is bent about a central hub member E on the block and is flattened out on the helical surface D. The metal strip is then marked off for the number of blades required and the blades are cut from the helical strip as shown. The inner ends of the blades are then reinforced in any suitable manner and the bolts 10 apphed when they are ready for final installation on the propeller proper as shown 111 Fig. 1. Each blade is thus formed from a helical strip of metal and this is certainly important as the entire area of these blades will be equally eflicient and effective. The propeller is secured by means of the hub 2 to the shaft of an engine of any suitable character and as such will be rotated thereby.

The propeller is of course intended for flying machines of the helicopter type and as such should prove exceedingly efficient, as numerous blades are presented with a pro portionate area and lifting capacity. Each blade becomes effective over its entire surface from end to end as each blade is out from a helical strip of metal. The peripheral speed of the blades is also great due to the distance between their inner and outer ends and the center of the hub 2. It is well known that the most effective area of a standard form of propeller is towards the tips thereof and that the inner ends of the blades and the hub proper have very low ef ficiency. This inefiicient portion of the blade is entirely eliminated in the present instance by providing the cylindrical shaped frame here illustrated. The driving hub 2 is disposed where it will effect comparatively little resistance, and as the frame B is open comparatively little resistance will be caused thereby. It may therefore be contended that practically all of the engine power exerted is transmitted into effective lifting capacity.

VVhile'the form employed is more or less specificallyillustrated, I wish it understood that changes may be resorted to within the scope of the appended claims. Similarly, that the materials and finish of the several parts employed may also be changed to suit varying conditions and applications.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. A propeller of the character described comprising a hub member, radially disposed spokes on said hub, a plurality of vertically disposed rods, one for each spoke, and said rods being secured to said spokes, said vertical rods being arranged in cylindrical formation, a plurality of rods wound about said Vertical rods in helical formation and secured to said vertical rods, and a plurality of propeller blades secured to the helically Wound rods and projecting radially outwardly from the same.

2. A propeller of the character described comprising a hub member, radially disposed spokes on said hub a plurality of vertically disposed rods, one for each spoke and said rods being secured to said spokes, said vertical rods being arranged in cylindrical for- .mation, a plurality of rods Wound about said vertical rods in helical formation and secured to said vertical rods a plurality of propeller blades arranged exterior of the helically Wound rods, said blades being rzdially disposed with relation to the hub, means for securing the blades to said rods, said means permitting the angle or pitch of each blade to be adjusted.

ALBERT KooLEn. 

